Larger wires at service drop

[Mark A. Timpani]

I never noticed this before. The wires from the pole look very small. Then at the mast they are bigger.

Could you please fill in the blanks for me with whats wrong here or what could happen vs the main breaker size?

[David A. Andersen]

One is copper and one Alu?

Same rating?

[Jeff Moore]

Appears that even the stranded Al wire changes sizes at the clamp. Interesting question and I wish I had an answer for you but APS or SRP own the incoming lines and maybe a call to them would help. Or one of the electrical folk on this site can shed some info on the setup.

[Jim Port]

This is quite typical as the utilities do not use the NEC tables to size their wires.

The conductors have different insulation ratings and can radiate heat better by being in free air.

It is quite common for the overheads not even to be upgraded when a service increase is done.

[David C. Macy]

Good answer Jim!! I actually new what you saying. (Electrical has been one of my weaker areas)

I have a question pertaining to the clamp on the stranded wire. Is this an acceptable method of attaching the 2 wires? Shouldn't a similar clamp be used like the other two wires?

[Mark A. Timpani]

They are both Al wires.

[brian winkle]

Originally Posted by dmacy

Good answer Jim!! I actually new what you saying. (Electrical has been one of my weaker areas)

I have a question pertaining to the clamp on the stranded wire. Is this an acceptable method of attaching the 2 wires? Shouldn't a similar clamp be used like the other two wires?

The other two wires DO have the same H tap, you just can't see them because they are covered. The neutral does not need to be covered. It is a POCO connection, they are all done like that here (Tucson Electric Power).

[Jim Port]

One strand inside the neutral is a steel wire. This provides the support for the triplexed cable. The clamp on the stranded wire has the steel passing thru and going to the eyebolt on the mast.

The insulated conductors do not need a clamp as the triplex construction is all supported off of the carrier strand. The cable acts as a unit.

[brian winkle]

Originally Posted by Jim Port

One strand inside the neutral is a steel wire. This provides the support for the triplexed cable. The clamp on the stranded wire has the steel passing thru and going to the eyebolt on the mast.

The insulated conductors do not need a clamp as the triplex construction is all supported off of the carrier strand. The cable acts as a unit.

The way he said "attaching the 2 wires" I think he is referring to the H tap.

[Marc D. Shunk]

Yes, it is not necessary to put an HTap cover on the neutral. The neutral conductor is bare to begin with, so putting a cover on the HTap of the neutral is pointless and wasteful. The HTap's themselves cost about 85 or 90 cents, but the covers are 4 to 5 dollars each.

[Mark A. Timpani]

Yes, but I am wondering about the smaller wire size coming from the pole then jumping up to a larger size into the meter and panel.

[Larry D. Kage]

Originally Posted by mtimpani

Yes, but I am wondering about the smaller wire size coming from the pole then jumping up to a larger size into the meter and panel.

Happy New Year Mark.

Jim answered your wondering in post #4:

http://www.nachi.org/forum/f19/large...87/#post461758

[Marc D. Shunk]

Originally Posted by mtimpani

Yes, but I am wondering about the smaller wire size coming from the pole then jumping up to a larger size into the meter and panel.

Well then, quit worrying so much.


It's completely normal. The power companies size their conductors to NESC rules, and electricians size their wires to NEC rules. Two different animals. Unless the customer is having problems that can be attributed to voltage drop (lights dim severely when you turn on the disposal, etc.), it's not even worth a comment.

[Mark A. Timpani]

Marc, I am not an electrician so bare with me.

My mother in laws house got upgraded from a 100amp to a 200 amp. The wires coming from the pole were 100amp wires and the power company changed them to a 200 - 300 amp size. Then those same size wires were brought down into the panel and a 200amp breaker was installed so the panel is a 200amp panel.

The wires in the note above look very small like 60 - 100amps. Are you saying its ok to put larger feed wires to the panel to upsize to 200amps?

[Pierre Belarge]

As mentioned by Jim earlier in the thread, the size of the conductors from the pole to the weatherhead are sized based on the Utility codes - NESC. The size of the conductors from the overhead splice (service point - which is the load side of the utility conductors - service drop), are sized on the NEC.

The utility company will size their conductors based on the past usuage. So, if there is a service change, from 100A to 200A without a load change, the utility company will not even change their conductors from the pole.

The Utility company will size their conductors based on usuage (utility bills) and any additional calculated load(s). This conductor size will still be smaller than the NEC requirement.